The closure apparatus referred to hereinbefore means an apparatus for making sausages with a generally pasty filling material in a flexible tubular case (for example a sausage casing). Those closure apparatuses (also referred to hereinafter as automatic clipping machines) usually function in such a way that the filled tubular case which is closed at one end is constricted at a location by means of so-called displacement elements and thereupon filling material in the constriction region is displaced by a movement in the direction of the axis of the tubular case. At least one closure element (or clip) is placed on the plaited end portion of the tubular case which is formed in that way, and closed. In that fashion, either interconnected chains of sausages can be produced or for example individual tubes or bags are closed. When using what are referred to as automatic double clipping machines, two mutually juxtaposed clips are simultaneously placed on the plaited end portion of the tubular case formed in the above-described manner and closed, whereupon the plaited end portion is severed between the two clips. In that way individual sausages are produced in series.
As in all areas of technology, it has also been possible in the past to increase the level of productivity in the field of the clipping machines, by a considerable amount. That requires suitable adaptation of the peripheral devices—thus including the magazine bar and the entire clip feed arrangement. The simplest known clip feed arrangements comprise a substantially vertically arranged magazine bar onto which a “finite” line of clips comprising a plurality of clips which are arranged in a successive row and which are joined by a sealing strip are drawn by hand. As is known, at its lower end near the closure apparatus, the magazine bar is turned in a radius such that the line of clips is fed horizontally to a separating window of the closure apparatus, the window generally being arranged perpendicularly. Here, at the exit from the magazine bar, the clip which is the leading one in the advance direction is separated from the line of clips for further processing therewith.
The advance movement in the case of that clip feed arrangement is usually produced by the force of gravity. The maximum supply of clips is predetermined by the capacity of the magazine bar. As the latter is arranged vertically by virtue of the drive action produced by the force of gravity and as it must be easily possible to reach the entry thereof for the purposes of manually drawing the lines of clips onto the magazine bar, its length and thus capacity are greatly restricted. It is only limitedly suitable for closure apparatuses which operate at high speed as continuous manual restocking of the magazine would be required.
For another situation of use, U.S. Pat. No. 3,189,220 discloses a horizontal belt and friction roller drive for finite lines of staples which are stored in an upstream-disposed vertical magazine and which are automatically fed therethrough under the effect of the force of gravity.
A clip feed arrangement which is also known and which is a further development is distinguished in that the line of clips is wound on a reel which—for hygiene reasons also—is suspended above the separating window, to provide a larger clip supply. The virtually “endless” line of clips is drawn off that reel and introduced into the entry of a magazine bar. The geometry of the magazine bar is essentially identical to that of the above-described magazine bar which however, because of the reel supply, no longer has to perform the function of forming the supply of clips. The vertical part of the magazine bar can therefore be shorter.
The advance movement in the case of that clip feed arrangement is usually produced by an active clip drive which engages the line of clips in the region of the magazine bar. Two drive mechanisms are known. On the one hand, the required drive force can be applied by way of two permanently or intermittently driven friction rollers which bear against the line of clips on opposite sides. Alternatively, it is also possible to provide a drive in which a linearly reciprocatable entrainment member which engages the line of clips produces the advance movement as a stepwise motion. A clip feed arrangement having such a drive is shown for example in U.S. Pat. No. 5,586,424 A. A development of that drive provides two linearly reciprocatable entrainment members which alternately produce a stepwise advance movement.
When the clip supply has been used up, that is to say the reel has been unwound, there is always a residual line of clips remaining between the reel body and the entry to the magazine bar, which, being in the form of a loose end, in the absence of guidance above the entry to the magazine bar, bends away or tilts in such a fashion that it no longer threads into the entrance to the magazine bar. Therefore the closure apparatus is stopped when the clip reel is empty. To change the clip supply the empty reel body has to be pulled down from its holder and the remaining line of clips has to be pulled out of the magazine bar in the opposite direction to the advance direction so that the leading end of a fresh line of clips can be threaded in.
The stoppage times which are caused by that magazine refilling operation are undesirable. In addition, at each change, a residual portion of the line of clips which cannot be put to use is left over. In order to improve the relationship of operating time to stoppage time and also to improve the relationship of clips used to remaining clips, the clip reels were increased to a capacity of several thousand clips. At that point however the endeavors to increase productivity and output hit a limit as generally the clip reels have to be lifted manually onto the holder provided for mounting them, so that the weight thereof cannot be further unlimitedly increased.